Pumping system for gas wells



Aug. 3, 1965 J. M. SOUTH PUMPING SYSTEM FOR GAS WELLS Filed Dec. 19, 1961 S Sheets-Sheet 1 I J/ J BYE Jame; M. Jay/4 INVENTOR.

A? QMWQQ Aug. 3, 1965 Filed Dec. 19, 1961 J. M. SOUTH PUMPING SYSTEM FOR GAS WELLS 3 Sheets-Sheet 2 J N I I 4 dame; /1 Jay/ INVENTOR.

ATTO/P/VEVJ J. M. SOUTH 3,198,134

PUMPING SYSTEM FOR GAS WELLS 3 Sheets-Sheet 3 Aug. 3, 1965 Filed Dec. 19, 1961 United States Patent 3,198,134 PUMPING SYSTEM FOR GAS WELLS James M. douth, Longview, Tex., assignor to US. Industries, line, a corporation of Delaware Filed Dec. 19, 1961, Ser. No. 160,476 2 Claims. (Cl. 103-231) This invention is an improved pumping system for removing liquids from wells producing both liquid and commercial quantities of gas.

Many wells produce a liquid such as water, oil or condensate together with commercial quantities of gas. Accumulation of such liquids in the bottom of the well is a great disadvantage in gas production. The accumulation of any liquid is disadvantageous, but water is the most troublesome liquid encountered. Water accumulates in the'bottom of the well; and as the well fills up with water, a considerable back pressure is exerted on the face of a producing formation. This back pressure due to head of water in the well may be large enough to substantially stop production of gas or at least cut down the rate of production to a fraction of what it otherwise would be. Accumulation of oil and condensate has a similar effect but usually to a lesser degree. In any case it is necessary to prevent undue accumulation of liquid in a well to enable efiicient production of gas.

Numerous devices have been developed for removing liquid from gas wells to prevent accumulation of a head of liquid which would lower the production of gas. Gas lifts and free piston systems have been suggested for this use, but have required either a constant pressure in the production tubing or in the annulus of the well or a development of a definite pressure for initiation of operation. Such controls are frequently undesirable as gas pressure in the well often will vary considerably from time to time due to fluctuation in demand for gas passed to a gas sales line and to fluctuation in the rate of production of gas and liquid.

It is an object of this invention to provide a system for pumping liquids from wells producing gas in which variations in gas pressure within the well do not interfere with the operations.

Another object is to provide an improved system of this class in which substantially all liquid entering the well accumulates in a liquid production tubing and not in the annulus of the well where it is in contact with the face of a producing formation and which is responsive only to difference in gas pressure in an upper part of the well annulus and gas pressure in an upper part of the liquid production tubing to initiate pumping action but which does not require a free piston as a part of the control system.

Another object is to provide a system of this class in which the controls are operated by gas pressure and no electrical or magnetic equipment of any kind is necessary.

. Another object is to provide a system of this type which is simple in construction, rugged and dependable in operation, cheap and easy to install and which requires no stainless steel or other nonmagnetic parts in a wellhead. Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a 3,198,134 Patented Aug. 3, 1965 the annulus of the well to a suitable gas sales line. The v gas production line contains a valve which is not opened widely, according to usual gas well practice, but is set to maintain gas pressure in the annulus of the well usually at not less than about 300- to 400 p.s.i. while producing commercial quantities of gas.

The pressure responsive motor valve in the liquid production line is of the type having a diaphragm which is spring pressed in one direction and responsive to fluid pressure to overcome the force of the spring and move the diaphragm in the opposite direction. A means for changing fluid pressure, i.e. applying or releasing fluid pressure, according to direction of spring pressure on the diaphragm is provided for controlling operation of the valve to open the same and permit flow of fluid upward through the liquid production line when a pressure differential between gas in the upper part of the liquid production tubing and gas in an upper part'of the well annulus increases to a selected value and to change pressure on the valve to close the valve after a selected time interval. The time interval chosen, of course, is dependent upon the rate of production of liquid by the particular well and an adjustable timer is included in the system to permit such selected differential pressure admits actuating fluid into a conduit system which is arranged to change pressure upon the diaphragm of the motor valve to open the valve. A timer actuated by introduction of such pressure to start a time interval and, at the end of said time interval, to change pressure upon the diaphragm of the motor valve to close the valve is connected in the conduit system.

If desired, the conduit system also may include a valve actuated by a time-delay device and be arranged to vent only gas in the system downstream of the time-delay device, thus preventing waste of gas normally vented from a system of this type. This modification is especially desirable in locations where gas passed to the gas sales line has a high sales value.

In the attached drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 illustrates schematically one application of a control system of this invention to a pumping system in which a motor valve in a liquid production line is normally spring pressed toward closed position;

FIG. 2 is a modification of the system of FIG. 1 Wherein the motor valve in the liquid production line is pressed FIG. 7 is a schematic representation of one type of motor valve useable with systems of my invention showv 7 into communication with liquid in the bottom of the well. The interior of liquid production tubing 14 communicates with liquid 15, preferably through an open bottom of tubing 14. Tubing14 communicates with a liquid withdrawal line 16 at a point adjacent to the surface of the earth, and a motor valve 17 or 17a is disposed so that the pair of diaphragms 37 and 370 are disposed on opposite sides of the plate. Space within housing 36 between plate 38 and the diaphragms is filled with a liquid 39. A line 40 communicates with the interior of the housing on each side of the plate so that when diaphragms 3'7 and 37a operate from one position to another the liquid 39 must flow through line 40. Line 40 contains a valve designated generally as 41 having an adjustable passageway 42 therethrough between a suitable'valve closure in line 16 to controlflow of fluid therethrough; The

numeral 17 in FIGS. 1 and 3 designates a motor valve .spring pressed toward closed position, andthe numeral 1.7a in FIGS. 2 and 4 designatesv a motor valve spring constant rate from an upperpart of the liquid productiontubing is illustrated asan adjustable self-cleaning choke 20 connected to bleed gasa'round motor valve 17 in liquid withdrawal line 16 when the motor: valve is closed;

Lines 21 and. 22 communicate respectively with an upper part of the annulus of the well and the interior of controller 24 on one side of a diaphragm 23, and the interior of the liquid production tubing 14 at an upper part thereof and the opposite side of diaphragm 23. Pressure diflerential between the annulus of the well and an upper part of the production tubing is thus exerted upon diaphragm 23. i

Controller 24 is shown in greater detail in FIG. 5; It comprises a housing 25 having a diaphragm 23 disposed across the interior thereof. is admitted through line 21 and port 21a to the interior of housing 25 on one side of diaphragm 23 while pressure from the gas in the upper part of the liquid production tubing isadmitted through line 22 and port 22a into the interior of the' housing onthe opposite side of diaphragm 23. Compression force of a spring 126 is transmitted through a suitable rod 127 attached to diaphragm 23 to supplement the force exerted by gas in the upper part of the liquid production tubing in balancing pressure from the annulus of the well exerted on diaphragm 23. It will thus be seen that, when pressure in an upper part of the liquid production tubing falls to a value sufficiently low that this pressure plus the pressure of spring 126 is not sufficient to overcome the force of gas pressure exerted on the upper side of diaphragm 23, the diaphragm will move downward. Arod 26 carrying a-three-way' valve designated generally as 27 is dis'posed'to close a vent 28 to the atmosphere and to connect an actuating pressure line 29 to linei30. It will be seen that upward movement of valve 27 closes the inlet from line 29 and connects,

line 30 with vent.28. p

In FIG. 1, line 30 is connectedto the inlet of a'nor- Pressure in the well annulusmember and a valve seat. Rate of flow of liquid from one side of plate 38 to the other in response to fluid pressure applied through line or in the opposite direction in response to pressureofspring 43 thus determines a time interval after application of fluid pressure through line 35 at which communication of fluid between lines 30 and 33 is discontinued.

' Thisv time interval may be easily adjusted to the rate of production of 1 liquid from any. particular'well. A suitable bleed orifice 44 is connected in line 33 to release gas under pressure trapped between valve 31 and the diaphragm of valve, 17 when valve 31 is closed by liquid production movement of the diaphragm in time 32. I

.The preferred type of bleedmeans illustrated as choke 20 is shown in greater. detail in FIG.v 7. Lines 48 and 49 communicatewith the interior of body 50'of valve 17 in a manner-to bleed gas around thepassageway forfluid around valve seat 51 when the latter is closed. The choke comprises a body having a passageway for fluid therethrough. A choke member 52 is disposed in the passageway to be pressed by pressure of spring into position to close the passageway. An adjustable stop member 53 also isdisposed inthev passageway to prevent the closure member 52from-closing the passageway completely; A suitable adjustment shown as a block nut 54 is provided to control the 'position of stopsmernber 53 and hence the degree of choke exerted by member 52.

7 Pressure from spring 55 is exerted on a diaphragm 56 to which the choke member 52 is connected. Line 46 communicates with the space in the body of 'the choke below this diaphargm so'that, when actuating pressure is admitted by controller 23 through lines. 30, 33,34 and 46, the choke member 52 is lifted out of contact with stop member 53; and the resulting rush of fluid through lines 48 and 49 flushes any accumulation of dirt, gum or grease from the. choke, thus preventing clogging of the choke under the most adverse circumstances.

One complete cycle of pumping operations will now be described for the system illustrated in FIG. 1 assuming that valve '17 is closed and that valve 19 is partially open, producing gas from the annulus of the well but maintaining pressure thereinJ Gas and liquid are driven byformation' pressure from the formation 12 through mally open valve, designated generally as 31, in timer,32.

A preferred type of timer is illustrated in greater detail in FIG. 6,. This timer' comprises a housing 36 having a pair'of diaphragms 37 and 37;: therein. A plate 38 ex-' tends through and closes the central part of the housing openings 13 in casing 11 into the well annulus. Since gas pressure in the upper part of the production tubing is being lowered at a substantially constant rateby bleed of gas through choke 20, pressure in the production tubing becomes appreciably less than pressure in the well annulus. Under-these conditions, pressure of gas in the well annulus onthe surface of liquid in the bottom of the well forces the liquid through the open bottom of the liquid production tubing 14. .The choke 20 is set by adjustment ofmember 53 so that gas pressure in the upper part of the liquid production tubing decreases at a rate substantially equalto the increase inhead of liquid within the production tube. Thus, it does not accumulate in the annulus of the well where, it can exerta liquid head upon the face of theproducing formation.

. When gas pressure in the upper part of theproduction tube has decreased by action of choke 20 sufiiciently to produce a predetermined pressure differential between that gas and gas in the annulus of the well, the con-- troller operates to open normally closed valve 27.. Operation of Valve 27 admits actuating fluid which may conveniently be gas from the upper part of the. well annulus introduced through a suitable pressure 37a downward.

Diaphragm 3711, however, can move downward only very slowly because of the resistance of liquid 39 which must flow through line and adjustable passageway 42 to a space between diaphragm 37 and plate 33 on the opposite side of the plate. Setting of passageway 42 thus determines a time interval which is begun by application of pressure to timer 32 and ends when suflicient liquid has been transferred to force diaphragm 37 downward closing the normally open valve 31 and discontinuing transfer of gas under pressure from line 30 to line 33.

When valve 31 closes, gas under pressure trapped in lines'33 and 34, the body of valve 17 and in line 46 is vented to the atmosphere through bleed orifice 44 and valve if the latter is used to supplement the bleed orifice.

The bleed orifice selected is sufficiently smaller in size than the effective area of lines 30 and 33 that it does not interfere with the build-up of actuating pressure in lines 33 and 34 when valve 31 is opened but is large enough to release gas under pressure trapped in these lines and spaces communicating therewith in a short interval after closing of valve 31.

Release of pressure on the diaphragm of valve 1'7 permits the valve to be closed by spring pressure and closing of this valve quickly equalizes pressure in the upper part of the liquid production tubing 14 and the annulus of the well. As this pressure equalizes, the differential pressure between the two becomes less than that required to operate controller 24 to open valve 27 and the valve closes and the cycle is ready to begin again. It will be observed that no source of power is required to operate this system other than the fluids under pressure normally supplied in the wall itself.

The modification in FIGURE 2 differs in construction and operation from that described under FIGURE 1 in that valve 17a is of the type normally pressed to open position by a spring and requiring application of pressure to close the valve. A line 57 is provided which admits pressure from line 21 through pressure reducing assembly 56 and line 57 and a normally open valve 58 to maintain valve 17a in closed position except when liquid is being produced. Valve 58 is a three-way type and preferably is constructed as shown which establishes communication between lines 57 and 59 when the valve is in one position and vents line 59 to the atmosphere when the valve is operated by fluid pressure. Line 34a communicating with lines 33 and 46 it arranged to apply actuating pressure to a diaphragm in the motor of valve 58.

The operation of this modification is obvious. With valve 17a in closed position pressure is applied through the pressure reducing assembly 56, line 57, valve 58 and line 59 to the diaphragm of valve 17a to hold this valve closed. Liquid in the liquid production tube accumulates, and the differential pressure between gas in the upper part of the liquid production tube and gas in the annulus in the well increases to a point where controller 24 operates to open valve 27. When this valve is opened, pressure is admitted through lines 30 and the normally open valve 31 to line 33 and 34a to move valve 58 to a position venting line 59 to the atmosphere so that valve 17a is opened by spring pressure. Pressure through line 35 operates timers 32 after a selected time interval to close the normally open valve 31. Pressure trapped in the motor of valve 58 and lines 34a, 33 and 46 is then bled off and valve 58 moves to a position connecting lines 57 and 59 so that the valve is again closed by pressure of gas admitted through line 59 and the cycle is repeated.

The modification shown in FIGURES 3 and 4 differs from the systems of FIGURES l and 2 by arrangement of apparatus to prevent waste of gas through bleed orifice 44-. It will be seen that the systems of FIGURES 1 and 2 result in a bleed of gas to the atmosphere at all times while liquid is being produced from the well. In many locations this gas has a high sales value and is worth an expenditure for extra equipment to prevent its loss. The

arrangements shown in FIGS. 3 and 4 accomplish this,

end.

This is accomplished by inserting a normally open valve having a time delay motor designatedgenerally as 60 disposed to control flow between lines 30 and 33a and inserting a valve 58a similar to the valve 58 described above disposed to vent line 63 to the atmosphere except when pressure is upon the diaphragm of the valve. Lines 57 and 63 communicate with each other through the valve when pressure is on the valve diaphragm. In the modification of FIG. 3, when the controller operates to admit actuating gas under pressure in line 30 through the normally open valve having a time delay motor 60 into the lines 33a and 34 to open valve 17, pressure also is applied through line 33a to move valve 58:: into position to establish communication between lines 57 and 63 and thus apply pressure to the timer 32. The time delay valve 60 is quite similar in construction to timer 32 except that fluid between the plate and the pair of diaphragms passes from one side of the plate to the other through an opening 61 of proper size drilled in the plate. This opening is sufiiciently large that the valve 60 operates in a shorter period of time after application of pressure through line 35 than does timer 32. The valve 60 closes in response to pressure and cuts 01f communication between lines 30 and 33a but leaves pressure trapped in line 33a and spaces communicating therewith in valves 58a and 17. Valve 58a thus continues to admit actuating pressure through lines 57 and 63 to the timer 32 and valves 58a and 17 remain in their fluid pressed position until timer 32 operates to release pressure through valve 27. On release of this pressure, force of the spring in the valve 17 returns the valve to its normally closed position, and the cycle begins again.

The modification shown in FIG. 4 is similar to that of FIG. 3 except that the valve 17a is spring pressed toward open position. Valve 58 is spring pressed to a position establishing communication between lines 57 and 63 and valve 27a in the timer 32 is spring pressed toward open position.

It will be seen that application of actuating pressure through line 30 and normally open time delay valve 60 to a diaphragm of valve 58 moves this valve to the position to vent line 59a and the interior of valve 17a on one side of the diaphragm to the atmosphere. At the same time, the space above the diaphragms in timer 32a is vented through line 63 so that spring pressure upon the diaphragm starts flow of liquid through line 40. Since time delay valve 60 operates in a shorter time than the minimum required for operation of valve 27a of the timer, it will be seen that both the valve 17a and timer are vented to the atmosphere by gas under pressure trapped in the upper part of valve 58 and lines communicating therewith until the timer operates to open valve 27a. Opening valve 27a vents valve 58 and communicating lines to the atmosphere, thus applying pressure from line 57 to the diaphragm in valve 17a to close the valve and to the upper side of the diaphragms in timer 32a to close valve 27a and the cycle of operations is repeated.

From the foregoing it Will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be seen that certain features and subcombinations 7 are of utility and'may be employed without reference to other features and sub'combinatio'ns. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made, of'the invention without departing from the scope thereof, it' is to be understood that all matter herein set forth or shown in the accompanying drawings is to, be interpreted as illustrative and not 'in a limiting sense. a i

The invention having been described, what is claimed 1. Agas lift system for moving liquid from a Well producing both gas and liquid comprising a gas production line connected with anannulus of a well; an adjustable ,valve, in the gas production line; production tubing for a liquid extending down into operative contact with, liquid in the well; a liquid withdrawal line-connected to the.

production tubing; means-for bleeding gas at a selected substantially constant rate from an upper part of the pro duction tubing; a fluid actuated motor valve disposed to 7 control flow through the liquid withdrawal line; a second fluid actuated motor valve; piping arranged to supply actu'-' ating fluid to both motor valves; a controller, including a spring loaded diaphragm responsive'to differential in pressure between gas in an upper part of the production tubing and gas in an annulus'of the well and 'a valve closure member operated by movement of the last 'rnentioned diaphragm controlling flow of actuated fluid through the controller and said piping to both said motor valves; a fluid actuated timer connected to vent actuating fluid from a a both said motor valves at expiration of a selected time interval after application of actuating pressure; and a bypass lineifrom said source of actuatingfluid to said fluid actuator timer, said second motor valve being disposed to control flow through said by-pass line. 7

2. The system of claim 1 further characterized by a fluid actuated time delay valve disposed to control flow of actuating fiuidfrom the controller to both motor valves,-

said time delay valve closing in a shorter time period than that required for the adjustable timer to vent said motor valves.

7 References Cited by the Examiner UNITED STATES PATENTS JOSEPH VH-VBRANSON, 5R. Primary Examiner; LAURENCE v. EENER, Examiner. I x 

1. A GAS LIFT SYSTEM FOR MOVING LIQUID FROM A WELL PRODUCING BOTH GAS AND LIQUID COMPRISING A GAS PRODUCTION LINE CONNECTED WITH AN ANNULUS OF A WELL; AN ADJUSTABLE VALVE IN THE GAS PRODUCTION LINE; PRODUCTION TUBING FOR LIQUID EXTENDING DOWN INTO OPERATIVE CONTACT WITH LIQUID IN THE WELL; A LIQUID WITHDRAWAL LINE CONNECTED TO THE PRODUCTION TUBING; MEANS FOR BLEEDING GAS AT A SELECTED SUBSTANTIALLY CONSTANT RATE FROM AN UPPER PART OF THE PRODUCTION TUBING; A FLUID ACTUATED MOTOR VALVE DISPOSED TO CONTROL FLOW THROUGH THE LIQUID WITHDRAWAL LINE; A SECOND FLUID ACTUATED MOTOR VALVE; PIPING ARRANGED TO SUPPLY ACTUATING FLUID TO BOTH MOTOR VALVES; PIPING ARRANGED TO SUPPLY ACTUSPRNG ALOADED DIAPHRAGM RESPONSIVE TO DIFFERENTIAL IN PRESSURE BETWEEN GAS IN AN UPPER PART OF THE PRODUCTION TUBING AND GAS IN AN ANNULUS OF THE WELL AND A VALVE CLOSURE MEMBER OPERATED BY MOVEMENT OF THE LAST MENTIONED DIAPHRAGM CONTROLLING FLOW OF ACTUATED FLUID THROUGH THE CONTROLLER AND SAID PIPING TO BOTH SAID MOTOR VALVES; A FLUID ACTUATED TIMER CONNECTED TO VENT ACTUATING FLUID FROM BOTH SAID MOTOR VALVES AT EXPIRATION OF A SELECTED TIME INTERVAL AFTER APPLICATION OF ACTUATING PRESSURE; AND A BYPASS LINE FROM SAID SOURCE OF ACTUATING FLUID TO SAID FLUID ACTUATOR TIMER, SAID SECOND MOTOR VALVE BEING DISPOSED TO CONTROL FLOW THROUGH SAID BY-PASS LINE. 